In our solution we will be focusing only on the rectangular rooms with the regular wave vector grid (regular eigenvalue lattices in the wave vector space) [1]} as shown in Figure REF . The k-space is an array of numbers representing spatial frequencies. According to theory, as long as we know the periodicity of the grid over each of the axes, it will provide us the knowledge on the room geometry as well as the values of the wave vectors of higher order. So the goal of our approach is the estimation of these three periods along each of the axes. Under the assumptions that the room is lightly damped, the 3 fundamental axial modes can be used as a basis to find all higher order modes. This will reduce the cutoff frequency of the analyzed data, which further reduces the density of the required grid of microphones, due to the dependencies between the temporal and spatial sampling as shown earlier.
